Chromosome 3 is 7% of the human genome and encompasses 230 megabases of DNA. A large number of new markers have been generated for chromosome 3, as evidenced by the number of DNA segments assigned to chromosome 3: there has been an increase from 100 markers to 1600 over the past 3 years. Several groups have constructed maps for chromosome 3. The purpose of this workshop is to consolidate data from many labs to construct physical, linkage and radiation maps for chromosome 3. To ensure that consensus maps are derived from this meeting, the participants will presubmit their data as a requirement for acceptance to the workshop. These maps will establish the common bases for the maps, identify overlap, identify areas that need resolution, and set up a resource for common reagents. The workshop will be two days in May, 1993 in Groningen, the Netherlands. The structure of the meeting will be a series of short presentations by each of the laboratories involved followed by an intense working session to resolve inconsistencies in the map and to produce consensus maps. Relevant material generated at this meeting will be presented in a published report.